Ms Bishop told MPs that ''anything could happen'' regarding the election date and that Ms Gillard would not necessarily be Labor leader when Australia went to the polls.

During Tuesday's meeting, Mr Abbott said that the Coalition could not assume they would win the election, declaring his side to be the underdog.

''Oppositions always are.''

In announcing the election date last month, Ms Gillard said that she had wanted to take the politics out of the issue and focus on policy.

Many senior Labor frontbenchers publicly backed the move, although there were reports of some criticism from within Labor about the early announcement.

Mr Rudd has continued to stand by his February 2012 statement that he would not challenge again for the Labor leadership.

Last week, Mr Rudd scoffed at reports he was within striking distance of toppling Ms Gillard.

On Tuesday, Ms Bishop also observed that Labor's next caucus meeting (on March 12) would fall during the week of the Ides of March.

''Who will be Julia Gillard's Brutus? Which close colleague will do the dirty work?''

Telling MPs that ''life imitates art'' in the Labor caucus, Ms Bishop recalled the assassination of Roman Emperor Julius Caesar, who was assassinated in the Roman Senate by a group of conspirators in 44 BC.

''Circle the next Ides of March in your diary, where chaos, history, a full moon and pandemonium will coincide,'' Ms Bishop said.

Continuing on the Shakesperean theme, Ms Bishop said that many people in Labor's caucus could pass for the character ''Bottom'' in A Midsummer Night's Dream.